go.mod

module github.com/Code-Hex/gql-filter

go 1.16

require (
	github.com/graphql-go/graphql v0.7.9 // indirect
	github.com/k0kubun/pp v3.0.1+incompatible // indirect
	github.com/mattn/go-colorable v0.1.8 // indirect
)

main.go

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"os"

	"github.com/graphql-go/graphql"
	"github.com/k0kubun/pp"
)

func main() {
	if err := run(context.Background()); err != nil {
		fmt.Fprintf(os.Stderr, "err: %+v", err)
		os.Exit(1)
	}
}

const j = `{
    "title": "example glossary"
}`

func run(ctx context.Context) error {
	var a interface{}

	if err := json.Unmarshal([]byte(j), &a); err != nil {
		return err
	}
	pp.Println(a)
	schemaConfig := graphql.SchemaConfig{
		Query: graphql.NewObject(
			graphql.ObjectConfig{
				Name:   "RootQuery",
				Fields: traverse(a),
			},
		),
	}
	schema, err := graphql.NewSchema(schemaConfig)
	if err != nil {
		return err
	}

	query := `
		{
			title
		}
	`
	params := graphql.Params{
		Schema:        schema,
		RequestString: query,
	}
	r := graphql.Do(params)
	if r.HasErrors() {
		return fmt.Errorf("errors: %+v", r.Errors)
	}

	result, err := json.Marshal(r)
	if err != nil {
		return err
	}
	pp.Println(string(result))
	return nil
}

func traverse(val interface{}) interface{} {
	switch typ := val.(type) {
	case map[string]interface{}:
		fields := graphql.Fields{}
		for k, v := range typ {
			tt := traverse(v)
			switch c := tt.(type) {
			case *graphql.Field:
				fields[k] = c
			}
		}
		return fields
	case string:
		return &graphql.Field{
			Type: graphql.String,
			Resolve: func(p graphql.ResolveParams) (interface{}, error) {
				return val, nil
			},
		}
	case int:
		return &graphql.Field{
			Type: graphql.Int,
			Resolve: func(p graphql.ResolveParams) (interface{}, error) {
				return val, nil
			},
		}
	case float32, float64:
		return &graphql.Field{
			Type: graphql.Float,
			Resolve: func(p graphql.ResolveParams) (interface{}, error) {
				return val, nil
			},
		}
	}
	return &graphql.Field{
		Type: graphql.String,
		Resolve: func(p graphql.ResolveParams) (interface{}, error) {
			return val, nil
		},
	}
}